Global Mangrove Watch

The Global Mangrove Watch (GMW) is an international initiative led by the Japan Aerospace Exploration Agency (JAXA) in collaboration with the University of New South Wales (Australia), Aberystwyth University (U.K.), solo Earth Observation (Japan), Wetlands International and the World Conservation Monitoring Centre (UNEP-WCMC).

The GMW aims to help countries safeguard against further mangrove forest loss and degradation by identifying the locations as well as the causes of natural and human-induced events and processes that are leading to change. To this end, the GMW seeks to provide annual maps of changes in global mangrove extent using Japanese JERS-1, ALOS and ALOS-2 radar satellites. When fully operational, the GMW aims to generate a global mangrove baseline for the year 2010 at 25m spatial resolution and change maps for the years 1996, 2007-2010 and annually from 2015 for all mangroves in the tropics and sub-tropics. To-date, mangrove maps have been generated over 16 prototype regions around the world for algorithm development and validation. A global (visual) overview of the satellite data composites has already established significant areas of mangrove loss but also expansion associated with, for example, increased sedimentation along coastlines. This analysis has highlighted the benefits of using these satellite time-series datasets for observing and describing the causes and consequences of change.

The GMW addresses issues with existing global mangrove datasets that are either based on relatively old data (e.g., the USGS survey based on 1997–2000 Landsat sensor data) or are inconsistent across countries (e.g., WCMC 1987 and 2010, which is a collation of maps from different sources). Ultimately, it is envisaged that GMW products will be used to help inform environmental policy and provide new ways to track progress towards international biodiversity targets, such as the Convention of Biological Diversity (CBD) Aichi targets.

Endorsed by the Ramsar Science and Technology Review Panel (STRP), the GMW is a pilot demonstration project to the Ramsar Global Wetlands Observation System (GWOS). The GMW coalition is now working to secure its adoption and implementation by policy makers and practitioners so that we can narrow the gap between science, policy and practice.